The present invention generally relates to a casting machine, and more particularly, to a casting apparatus capable of manufacturing, with an extremely high efficiency, small-sized spherical metal lumps or ingots suitable for being supplied, for example, into a metal melting pot for a die-casting machine, type casting machine or the like through rolling movement of the metal lumps over a supply trough.
Commonly, spherical metal lumps or ingots may be fed into the metal melting pot through rolling movement thereof, and therefore, are extremely advantageous as compared with the case where rectangular ingots are supplied through sliding, since there is no possibility of accumulation of the metal lumps during feeding of such spherical metal lumps. However, molten metal generally shrinks in its volume during solidification, and thus, in the conventional spherical metal lump casting machines, when molten metal is injected through pouring gates into spherical cavities formed in casting molds for subsequent cooling, sink marks or shrink marks which open toward the spherical surfaces of the metal lumps are formed, and the openings of such shrink marks hinder smooth rolling of the spherical metal lumps during feeding. Moreover, if voids due to such shrinkage are formed within the spherical metal lumps during the solidification so as to allow entry of external air thereinto, there are such dangers that the air contained in the voids is heated and expands upon feeding of the metal lumps into the metal melting pot so as to cause explosions or that the molten metal in the pot is brought into a boiling state.